ExtendedPropertyPlaceholderConfigurer.java

/*
 * RED5 Open Source Flash Server - http://code.google.com/p/red5/
 * 
 * Copyright 2006-2012 by respective authors (see below). All rights reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.red5.spring;

import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Properties;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;

/**
 * An extension of {@link PropertyPlaceholderConfigurer}. Provides runtime
 * additions of properties and wildcard location lookups.
 * 
 * Properties can be added at runtime by using the static
 * {@link #addGlobalProperty} before* the bean definition is instantiated in the
 * ApplicationContext. A property added by {@link #addGlobalProperty} will get
 * merged into properties specified by the bean definition, overriding keys that
 * overlap.
 * 
 * wildcard locations can be used instead of locations, if both are declared the
 * last will override. Wildcard locations are handled by
 * {@link #setWildcardLocations(String[])}, using
 * {@link PathMatchingResourcePatternResolver} for matching locations. For
 * wildcard locations that matches multiple Properties files, they are merged in
 * by alphabetical filename order.
 * 
 * @author Michael Guymon (michael.guymon@gmail.com)
 * 
 */
public class ExtendedPropertyPlaceholderConfigurer extends
		PropertyPlaceholderConfigurer {

	private static Logger logger = LoggerFactory
			.getLogger(ExtendedPropertyPlaceholderConfigurer.class);

	private static Properties globalPlaceholderProperties = new Properties();

	private Properties mergedProperties;

	@Override
	protected void processProperties(
			ConfigurableListableBeanFactory beanFactoryToProcess,
			Properties props) throws BeansException {

		props.putAll(copyOfGlobalProperties());
		logger.debug("Placeholder props: {}", props.toString());

		this.mergedProperties = props;

		super.processProperties(beanFactoryToProcess, props);
	}

	/**
	 * Merged {@link Properties} created by {@link #processProperties}
	 * 
	 * @return {@link Properties}
	 */
	public Properties getMergedProperties() {
		return mergedProperties;
	}

	/**
	 * String[] of wildcard locations of properties that are converted to
	 * Resource[] using using {@link PathMatchingResourcePatternResolver}
	 * 
	 * @param locations
	 *            String[]
	 * @throws IOException
	 */
	public void setWildcardLocations(String[] locations) throws IOException {

		List<Resource> resources = new ArrayList<Resource>();
		PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(
				this.getClass().getClassLoader());

		for (String location : locations) {
			logger.debug("Loading location {}", location);
			try {
				// Get all Resources for a wildcard location
				Resource[] configs = resolver.getResources(location);
				if (configs != null && configs.length > 0) {
					List<Resource> resourceGroup = new ArrayList<Resource>();
					for (Resource resource : configs) {
						logger.debug("Loading {} for location {}", resource
								.getFilename(), location);
						resourceGroup.add(resource);
					}
					// Sort all Resources for a wildcard location by filename
					Collections.sort(resourceGroup,
							new ResourceFilenameComparator());

					// Add to master List
					resources.addAll(resourceGroup);

				} else {
					logger.info("Wildcard location does not exist: {}",
							location);
				}
			} catch (IOException ioException) {
				logger.error("Failed to resolve location: {} - {}", location,
						ioException);
			}
		}
		this.setLocations(resources.toArray(new Resource[resources
				.size()]));
	}

	/**
	 * Add a global property to be merged
	 * 
	 * @param key
	 *            String
	 * @param val
	 *            String
	 */
	public static synchronized void addGlobalProperty(String key, String val) {
		globalPlaceholderProperties.setProperty(key, val);
	}

	/**
	 * Copy of the manual properties
	 * 
	 * @return {@link Properties}
	 */
	private static synchronized Properties copyOfGlobalProperties() {
		// return new Properties( runtimeProperties ); returns an empty prop ??

		Properties prop = new Properties();
		prop.putAll(globalPlaceholderProperties);

		return prop;
	}

	public static class ResourceFilenameComparator implements Comparator<Resource>, Serializable {

		private static final long serialVersionUID = -6365943736917478749L;

		public int compare(Resource resource1, Resource resource2) {
			if (resource1 != null) {
				if (resource2 != null) {
					return resource1.getFilename().compareTo(
							resource2.getFilename());
				} else {
					return 1;
				}
			} else if (resource2 == null) {
				return 0;
			} else {
				return -1;
			}
		}

	}

}